In addition to the company's statement, the San Francisco Chronicle got its hands on the proposal documents from the Port of San Francisco through a FOIA request, and learned even more about the barges:
When it’s done, the barge’s backers say, the 50-foot-tall, 250-foot-long structure made of recycled shipping containers will be flanked by sails “reminiscent of fish fins, which will remind visitors that they are on a seaworthy vessel.”
“The structure will stand out,” the team says, in what is probably an understatement.
By and Large LLC, which submitted the barge documents, refers to the vessel as a “studio” and “temporary technology exhibit space.” It says its goal is to “drive visitation to the waterfront.”
The group that submitted the proposal expect the barges to attract around 1,000 visitors per day when it docks for a month at a time around San Francisco and then other waterfronts on the West Coast. The same routine presumably applies for the barge in Portland, Maine. A spokeswoman for the San Francisco Port said that the idea was "part of a preliminary proposal. They haven’t come back to us with anything concrete."
A slideshow of mockups for what the finished building might look like can be found over at CNET.